Portable pneumatic reversible drilling-machine.



C. SGHOFIELD.

PORTABLE PNEUMATIC REVERSIBLE DRILLING MACHINE. APPLICATION FILED 11111117, 1909.

1,008,076. Patented Nov. 7, 1911.

EVn??? 719 (hr/w 50Q2Z4 COLUMBIA PLANUGRAPH 1:0 WASHINGTON u 1.

CHARLES SCHOFIELD, OF NEWCASTLE-UPON-TYNE, ENGLAND.

PORTABLE PNEUMATIC REVERSIBLE DRILLING-MACHINE.

Specification of Letters Patent.

Application filed June 7, 1909.

Patented Nov. 7, 1911. Serial No. 500,472.

'l o all whom it may concern.

Northumberland, in England, have invented certain new and useful Improvements in Portable Pneumatic Reversible Drilling- Machines, of which the following is a specification.

This invention relates to portable pneumatic drilling machines more particularly of that class in which the controlling and reversing valve for motive fluid is rotated to cover and uncover ports in a seating disk whereby the motive fluid is admitted to opposite sides of the cylinder valves according to the direction of movement. In known apparatus of this class a circular valve has been rotated by means of an exterior sleeve operating an auxiliary member within the fluid supply pipe said valve being also provided with a series of circular apertures and recesses co-acting with the inlet ports in the seating valve and also with an exhaust port therein which communicates with a series of radial channels leading to a pcripheral exhaust. channel.

The object of the present invention is to considerably simplify the construction and operation of such controlling and reversing valve mechanism, this being accomplished byrotation of the fluid supply pipe itself and connecting such pipe by means of an eccentric pin or equivalent with a valve of D type which is notprovided with any ports therethrough and is guided in its movements over the seatingdisk to cover and uncover the ports therein by means of a slotted disk or the like. The seating disk itself is also of simplified construction having a single radial passage from the central exhaust port to the peripheral channel above mentioned.

The invention is represented in the annexed drawings in which- Figure 1 is a central section on the line A-A of Fig. 2 of a drill having two cylinders and embodying my invention. Fig. 2 is a section on the line BB of Fig. 1, and Fig. 3 is aplan view of the slide valve and slotted disk in operative relation with the valve face.

Referring to the drawings 2 designates the casing, 3 and 4 the cylinders provided respectively with the rotary valves 5 and 6 operated by eccentrics 7 and 8 respectively on the crank shaft of the apparatus.

The reversing valve 11 is of the D type of slide valve said valve being loosely connected to the inner end of the air pipe or tube 12 of the machine, and moved backward or forward on the valve face, by turning said air tube, through the medium of an eccentric pin 13 on the end of the tube engaging in a slot 1 1 at the back of the valve. The valve face 15 consists of a circular disk of suitable thickness fixed in the machine casing 2. There are two ports through the disk at a certain distance apart, one of said ports 16 opens into a chamber 17 in communication with the underside of the cylinder valves 5 and 6, the air passing thence up the center 18of each valve and through the ports to the cylinders thus driving the drill forward. The other port 19 through the disk 15 opens into a chamber 20 in communication by means of ports 20 with the outer edge or back 21 of the cylinder valves, and into which the air from the cylinders exhausts when the drill is running forward. Between the two said ports 16 and 19 in the disk is an exhaust port 22 which does not pass through the disk but is in communication with a hole or port 23 in the body of the disk leading to a groove or space 2 1 in its circumference, and a hole 25 in the casing opposite to said groove allows the exhaust to pass into the atmosphere. The casing is shaped to receive an attachment 26 which forms a valve chest, and also serves as a guide for the air pipe or tube 12 which is fitted into and is free to revolve therein. Within the valve chest is a slotted disk or the like 27 which engages and serves as a guide for the D valve, and by turning the air tube, the valve is caused to move to such an extent that either of the two through ports 16 or 19 in the disk can be opened to the air pressure in the valve chest. Therefore if the port 16 which opens into the chamber 17 in communication with the underside of the cylinder valves 5 and 6 is open, the drill will be driven forward and the exhaust will pass through the other port 19. If however the said port 19 which opens into the chamber 20 in communication with the back of the cylinder valves 5 and 6 is open, the motion of the drill is reversed, and it runs backward. The outer end of the air tube 12 is provided with the usual coupling 28 for attachment to the air main supply. For the purpose of turning, a sleeve or handle 29 encircles the air tube, and is suitably connected thereto.

What I claim as my invention and desire to secure by Letters Patent is In a pneumatic drilling machine, the combination of a disk having ports therethrough communicating respectively with alternately operated cylinder valves, said disk being provided with a single exhaust passage communicating with a groove in the periphery thereof, a D-valve slidably mounted on the disk adapted to close one of the ports and permit communication between the other port and the exhaust passage, a frame surrounding the valve for limiting the movement of same, the valve being provided with a protuberance having a lateral U-shaped recess, an axially rotatable fluid supply pipe, and an eccentrically arranged projection on the end of the fluid supply pipe for engaging the wall of the U-shaped recess whereby the D-valve will be operated by the rotation of said fluid supply pipe, substantially as described.

In witness whereof I have signed this specification in the presence of two Witnesses.

CHARLES SGHOFIELD. lVitnesses:

A. H. B. WILSON, J. B. Sonormm).

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

